The present invention relates to a process for producing bond wire connections and an assembly carrier made by the process.
It is known to use a process to electrically connect the electronic components such as, for example, semiconductor chips, which are assembled on an assembly carrier on board with the conductor path frame of the assembly carrier or board. In this process, the connection of the chips is accomplished in a so-called ball-wedge-bonding process in which bonded wire is connected with connection surfaces (bond surfaces) to which the conductor paths are oriented. During the ball-wedge-bonding, the wire is guided by a capillary of the bonding head. A remote first end of the wire is melted, for example, via a signal discharge device and a ball is formed due to the outer surface tension of the melted end. A weld is then formed between the electronic component connection of an electronic component on the assembly carrier and the first end of the wire via a so-called thermal welding in which pressure, heat and ultrasound effects are applied during the lowering of the capillary onto the electronic component connection. Thereafter, the capillary is moved to the connection surface of a conductor path during which movement the wire is drawn out of the capillary.
During the lowering of the capillary a second end of the wire is applied to the connection surface of the conductor path and is widened out as it is applied by the action of the capillary rim there against the wedge as well as welded to the connection surface by the action of pressure, heat, and ultrasound effects of thermal welding. The second end of the wire is created as the wire is severed from the wire supply in the capillary during the wire end application process just described. A disadvantage arises with this known process, however, in that the creation of the second thermal weld connection involving widening out of the second end of the wire requires considerably more working space than the creation of the ball on the first end of the wire as it applied to the electronic component connection. The distance between adjacent electronic component connections can on a chip, for example, amount to only 80 .mu.m while, in contrast, the width of the connection surfaces of the conductor paths must be chosen at some multiple greater than this distance, in order to permit sufficient working room to lower the bonding tool to the connection surface. For this reason, the matrix or arrangement of the connection surfaces associated with the conductor paths is relatively much larger than the matrix or arrangement of the electronic component connections and requires much more space on the assembly carrier. Moreover, it is disadvantageous that the space between the connection surfaces of the conductor paths and the electronic component connections are not otherwise available for use since the wires extend over the space.